This invention relates to an equipment assembly, and is particularly applicable to such an assembly in which a large number of electrical contacts are made with an electrical backplane when a sub-unit is inserted into the equipment. Each individual electrical contact may be fragile and easily damaged, and although the force needed to make a single electrical contact, e,g., by inserting a conductive pin into a socket is small, the total force needed to make a large number, eg many hundred, of contacts simultaneously will be very large indeed. It is very difficult to apply such a large force to the sub-unit as a whole without serious risk of damage to individual electrical contacts.